Microporous diffusion apparatus

ABSTRACT

Apparatus for active in situ multi-element gas sparging for bioremediation or physico-chemical degration for removal of contaminants in a soil formation containing a subsurface groundwater aquifer or a substantially wet unsaturated zone, the multi-gas contained in bubbles, wherein the apparatus includes a plurality of injection wells extending to a depth of a selected aquifer; introducing an oxidizing agent comprising ozone mixed with ambient air to provide a multi-element gas by means of microporous diffusers, without applying a vacuum for extraction of stripped products or biodegration by-products, wherein said diffusers form micro-fine bubbles containing said multi-element gas that oxidizes, by stripping and decomposition, chlorinated hydrocarbons from the aquifer and surrounding saturated soil formation into harmless by-products; also including a pump for agitating water in the well selecting microbubbles, injecting them into the aquifer and effective to alter the path of micro-fine bubbles through a porous solid formation whereby enhanced contact between the oxidizing agent contained in each said bubble by stripping pollutant from solution in ambient water into the mini-atmosphere of each bubble effective to increase the efficiency and speed of remediation of a site.

CROSS-REFERENCE To RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 29/038,499 entitled Bubblersparge Unit for GroundWater Treatment to William B. Kerfoot filed on May 5, 1995 and U.S.patent application Ser. No. 08/638,017, entitled Groundwater and SoilRemediation with Microporous Diffusion Methods and Apparatuses, toWilliam B. Kerfoot filed on Apr. 25, 1996, which are incorporated hereinby reference.

BACKGROUND OF INVENTION

1. Field of the Invention (Technical field)

The present invention relates to apparatuses for remediation ofdissolved chlorinated hydrocarbons in aquifer regions by injectingmicro-fine bubbles effective for active in situ groundwater remediationfor removal of dissolved chlorinated hydrocarbon solvents and dissolvedhydrocarbon petroleum products. Remediation of saturated soils may alsobe obtained by employment of the present invention.

2. Background Prior Art

There is a well recognized need to cleanup of subsurface leachate plumesin aquifer regions and contaminated sites including in particular,dry-cleaning establishments and U.S. Military Air bases. Applicant isaware of prior art devices that have used injection of air to facilitatebiodegradation of plumes.

However there has not been shown apparatus for remediating a site in acontrolled manner of poorly biodegradable organics, particularlydissolved chlorinated solvents with micro-fine bubbles including amulti-gas oxidizing agent.

In fact the Federal Agency (EPA, KERR Environmental Laboratory, ADA,Oklahoma) responsible for review of clean-up procedures at Marine CorpAir Base at Yuma, Ariz. has determined that there is no prior referenceswhich disclose the use of the present invention and has orderedindependent pilot tests to provide test results confirming the resultspreviously obtained by the present invention.

In U.S. Pat. No. 5,221,159, to Billings shows injection of air intoaquifer regions to encourage biodegradation of leachate plumes whichcontain biodegradable organics together with simultaneous soil vacuumextraction.

In U.S. Pat. No. 5,269,943, METHOD FOR TREATMENT OF SOILS CONTAMINATEDWITH ORGANIC POLLUTANTS, to Wickramanayake shows a method for treatingsoil contaminated by organic compounds wherein an ozone containing gasis treated with acid to increase the stability of the ozone in the soilenvironment and the treated ozone applied to the contaminated soil todecompose the organic compounds.

In U.S. Pat. No. 5,525,008, REMEDIATION APPARATUS AND METHOD FOR ORGANICCONTAMINATION IN SOIL AND GROUNDWATER, to Wilson provides a method andapparatus for in-situ treatment of soil and groundwater contaminatedwith organic pollutants. It involves concentration of a reactivesolution required to effect treatment of the contaminated area;injecting the reactive solution into one or more injectors that areinserted into the ground, scaled and positioned so as to assure flow andallowing reactive solution to flow through the contaminated area therebyreacting chemically. Preferably, the reactive solution is an aqueoussolution of hydrogen peroxide and metallic salts.

In U.S. Pat. No. 5,178,755, UV-ENHANCED OZONE WASTEWATER TREATMENTSYSTEM, to Lacrosse ozonated liquid is mixed within a multi-stageclarifier system with wastewater to be treated and suspended solids areremoved.

However, notwithstanding the teachings of the prior art, there has notbeen shown apparatus for remediating a site in a control led manner ofpoorly biodegradable organics, particularly dissolved chlorinatedsolvents with micro-fine bubbles including an encapsulated multi-gasoxidizing agent. The present invention accomplishes this by employingmicroporous diffusers injecting multi-gas bubbles containing an ozoneoxidizing agent into aquifer regions to insitu strip and rapidlydecompose poorly biodegradable organics or to accelerate biodegradationof leachate plumes which contain biodegradable organics which overcomesat least some of the disadvantages of prior art.

SUMMARY OF THE INVENTION

The present invention relates to sparging apparatus for injection ofoxidizing gas in the form of small bubbles into aquifer regions toencourage in situ remediation of subsurface leachate plumes.

In particular the present invention is directed to sparging apparatusesfor employing microporous diffusers for injecting micro-fine bubblescontaining encapsulated gas bubbles into aquifer regions to encouragebiodegradation of leachate plumes which contain biodegradable organics,or Criegee decomposition of leachate plumes containing dissolvedchlorinated hydrocarbons. The sparging apparatuses of the presentinvention, employing microporous diffusers for injecting an encapsulatedmulti-gas oxidizing agent, are particularly useful in that theapparatuses promote extremely efficient removal of poorly biodegradableorganics, particularly dissolved chlorinated solvents, without vacuumextraction of undesirable by-products of remediation and whereinremediation occurs by employing encapsulated multi-gas oxidizing agentfor destroying organic and hydrocarbon material in place with withoutrelease of contaminating vapors.

Unlike the prior art, the contaminated groundwater is injected with anair/ozone mixture wherein micro-fine air bubbles strip the solvents fromthe groundwater and the encapsulated ozone acts as an oxidizing agent ina gas/gas reaction to break down the contaminates into carbon dioxide,very dilute HCL and water. This system is known as the C-Sparge system.

The present invention, hereinafter C-Sparger system (tm) is directed tolow-cost removal of dissolved chlorinated hydrocarbon solvents such asperc from contaminated soil and groundwater aquifers. The C-Sparger(tm)system employs microporous diffusers, hereinafter Sparge Points (R) forproducing micro-fine bubbles containing an oxidizing agent thatdecomposes chlorinated hydrocarbons into harmless byproducts. TheC-Sparger (tm) also incorporates pumps means for pumping the anmulti-gas oxidizing mixture through the Spargepoint diffuse intogroundwater in a soil formation; a bubble production chamber to generatebubbles of differing size, a timer to delay pumping until large bubbleshave segregated from small bubbles by rise time, and a pump which forcesthe fine bubbles and liquid out into the formation. The pump meansintermittently agitates the water in the well in which the C-Sparger isinstalled which is effective to disturb the normal inverted cone-shapedpath of the bubbles injected by the sparge point through the soilformation and disperses them in a random manner, ensuring improvedcontact between the oxidizing agent (contained in each bubble) bystripping the pollutant from solution in the water into themini-atmosphere contained in each bubble. The pulsing action promotesmovement of the bubbles through the porous formation. It is the insitustripping action and maintenance of low solvent gas concentration in thebubbles which increases the efficacy and speed (and resulting cost) ofremediation of a site.

The apparatus of the present invention for removal contaminants fromsoil and an associated subsurface groundwater aquifer using microporousdiffusers in combination with a multi-gas system are particularly usefulin that the system promotes extremely efficient removal of poorlybiodegradable organics, particularly dissolved chlorinated solvents,without vacuum extraction, and wherein remediation occurs by destroyingorganic and hydrocarbon material in place with without release ofcontaminating vapors.

In the present invention the microporous diffusers and multi-gas systemcomprises oxidizing gas encapsulated in micro-bubbles generated frommicroporous diffusers matched to soil porosity. A unique bubble sizerange is matched to underground formation porosity and achieves dualproperties of fluid like transmission and rapid extraction of selectedvolatile gases, said size being so selected so as to not to be so smallas to lose vertical mobility. In order to accomplish a proper matching,a prior site evaluation test procedure is devised to test effectivenessof fluid transmission at the site to be remediated.

The advantage of controlled selection of small bubble size promotesrapid extraction of selected volatile organic compounds, such as PCE,TCE, or DCE with an exceptionally high surface to gas volume ratio. Thedual capacity of the small bubble production pulsed injection and risetime is matched to the short lifetime of an oxidative gas, such as ozoneto allow rapid dispersion into predominantly water-saturated geologicalformations, and extraction and rapid decomposition of the volatileorganic material. The unique apparatus of the present invention providesfor extraction efficiency with resulting economy of operation bymaximizing contact with oxidant by selective rapid extraction providingfor optimum fluidity to permit bubbles to move like a fluid throughmedia which can be monitored.

The use of microporous diffuser points provides a more even distributionof air into a saturated formation than the use of pressurized wells. Asparge system installed to remediate contaminated groundwater is mademore cost-effective by sparging different parts of the plume area atsequenced times. Through the proper placement of sparge locations andsequence control, any possible off-site migration of floating product iseliminated. With closely spaced sparge points, water mounding is used toadvantage in preventing any off-site escape of contaminant. The moundingis used to herd floating product toward extraction sites.

In the present invention, the microporous diffusers and multi-gassystem, hereinafter referred to as C-Sparger TM Systems are designed toremove dissolved organics and solvents (chlorinated hydrocarbons) suchas PCE, TCE, and DCE from contaminated groundwater. The micro-finebubbles produced by the Spargepoint. diffusers contain oxygen and ozonewhich oxidize the chlorinated hydrocarbons to harmless gases and weakacids. High initial concentrations of these dissolved organics havebeen, under (some specific-circumstances, reduced to levels of 1 ppb orless in periods of a-few weeks. None of the models to date are designedfor explosive environments.

The present invention employs a plurality of configurations consistingof Series 3500 and Series 3600 C-Sparge models. The 3600 Series islarger and has more capacity. Specifically, the 3600 Series has a bettercompressor rated for continuous use, a larger ozone generator, a secondspargepoint below the first in each well, and larger diameter gastubing. Both model series have control units that can support: one(Models 3501 & 3601), two (Models 3502 & 3602) and three separate wells(Models 3503 & 3603). The-*differences between the one, two, and threewell models are in the numbers of relays, internal piping, externalports and programming of the timer/controller.

Normal operation for C-Sparger TM systems includes carrying out, inseries for each well, the following functions on a timed basis: pumpingair & ozone through Spargepoint diffusers into the soil formation,pumping aerated/ozonated water in the well into the soils and recoveringtreated water above. Treatment is followed by a programmable period ofno external treatment and multiple wells are sequenced in turn.Agitation with pumped water disturbs the usually inverted cone-shapedpath of bubbles through the soils and disperses them much more widely.This increases contact and greatly improves efficiency and speed ofremediation. Vapor capture is not normally necessary.

Series 3500 and 3600 systems include a control Module (Box), one tothree well assemblies depending on specific model selected, a 1-00 ftsubmersible pump power-gas line for each well, a flow meter (to checkspargepoint flow rates). Model Series 3500 & 3600 Control Modules havebeen successfully deployed outdoors in benign and moderate environmentsfor prolonged periods of time. The Control Module must be firmly mountedvertically on 4×4 posts or a building wall near the wells.

The actual placement depths, separations, number/size of wells andoverall remediation system geometry are highly variable. Differences inspecific pollutant, spill, soil, groundwater and climate characteristicscan greatly influence the design and geometry of the overall remediationsystem. Monitoring wells are usually also needed. In short, specificcircumstances and conditions are often critical, however, a generic ortypical overall system is shown on FIG. 1.

Table I provides the basic specification for the Series 3500 & 3600systems. The drawing shows a single well system Series 3600 ( M-3601).The Series 3500 does not have the lower Spargepoint Multiple well models(3502, 3503, 3602 & 3603) just replicate the well units using a singleControl Module. FIG. 2 shows a piping schematic and FIG. 3 an electricalschematic for a 3 well system (Model 3503 or 3603). Current production3500 and 3600 Series models have an internal Ground Fault Interruptorand surge buffers incorporated into various electrical components. FIG.4 shows an internal layout of the Control Module box for a three wellsystem (M-3503 or M-3603). FIG. 5 shows the geometry of the bottom panelon the Control Module identifying the external connections and ports forthree well units (M-3503 & 3603). Table 2 lists fuses and theirlocations.

The Unique Use of Microfine Bubbles for SimultaneousExtraction/Decomposition.

The use of microporous Spargepoint diffusers to create fine bubbles,which easily penetrate sandy formations to allow fluid flow, hasunexpected benefits when used with multiple gas systems. Microfinebubbles accelerate the transfer rate of PCE from aqueous to gaseousstate. The bubble rise transfers the PCE to the vadose zone. Theten-fold difference in surface-to-volume ratio of spargepoint diffusermicrobubbles compared to bubbles from well screens results in afour-fold improvement in transfer rates. To block the gaseous state fromreverting to surface dissolved state in the vadose (unsaturated) zone, amicroprocessor system shuttles an oxidizing gas through the vadose zoneto chemically degrade the transported PCE.

Gaseous Exchange

If gaseous exchange is proportional to available surface area, withpartial pressures and mixtures of volatile gases being held constant, ahalving of the radius of bubbles would quadruple (i.e. 4x) the exchangerate. If, in the best case, a standard well screen creates air bubblesthe size of a medium sand porosity, a microporous diffuser of 20 micronsize creates a bubble one tenth ( 1/10) the diameter and then times thevolume/surface ratio. TABLE 2 Diameter Surface Area Volume (microns) 4r²) (4/3 r³) Surface Area/Volume 200 124600 4186666 .03 20 1256 4186 .3Theoretically, the microporous bubbles exhibit an exchange rate of tentimes the rate of a comparable bubble from a standard ten slot wellscreen.Partitioning Enhancement

Soil Vapor concentrations are related to two governing systems: waterphase and (non-aqueous) product phase. Henry's and Raoult's Laws(DiGiulio, 1990) are commonly used to understand equilibrium-vaporconcentrations governing volatization from liquids. When soils aremoist, the relative volatility is dependent upon Henry's Law. Undernormal conditions (free from product) where volatile organic carbons(VOC's) are relatively low, an equilibrium of soil, water, and air isassumed to exist. The compound, tetrachloroethane (PCE), has a highexchange coefficient with a high vapor pressure (atm) and low aqueoussolubility (umole/1). By enhancing the exchange capacity at least tenfold, the rate of removal should be accelerated substantially.

Ozone is an effective oxidant used for the breakdown of organiccompounds in water treatment. The major problem in effectiveness is ashort lifetime. If ozone is mixed with sewage-containing waterabove-ground, the half-life is normally minutes.

However, if maintained in the gaseous form, the half-life of ozone canbe extended to a half hour. Using the microbubbles as extracting agents,pulling chlorinated solvents out of the dissolved state into the gaseousform as they enter the bubbles ozone. The small bubbles high surface tovolume ratio accelerates a) the exchange area and b) the consumption ofHVOC within the bubble maximizes the (C_(S)—C) term. In reality therate-limiting process is the area-specific diffusion (dominated byHenry's Constant), while the decomposition reaction occurs rapidly(assuming sufficient ozone). Ozone reacts quickly and quantitativelywith PCE to yield breakdown products of hydrochloric acid, carbondioxide, and water.

To offset the short life span, the ozone could be injected withmicroporous diffusers, enhancing the selectiveness of action of theozone. By encapsulating the ozone in fine bubbles, the bubbles wouldpreferentially extract volatile compounds like PCE from the mixtures ofsoluble organic compounds they encountered. The ozone destruction oforganics would then target volatile organics selectively pulled into thefine air bubbles. Even in a groundwater mixture of high organic contentlike diluted sewage, PCE removal could be rapid.

The unique combination of microbubble extraction and oione degradationcan be generalized to predict the volatile organic compounds amenable torapid removal. The efficiency of extraction is directly proportional toHenry's Constant which serves as a diffusion coefficient for gaseousexchange (Kg).

In wastewater treatment the two-film theory of gas transfer (Metcalf andEddy, Inc, 1991) states the rate of transfer between gas and liquidphases is generally proportional to the surface area of contact and thedifference between the existing concentration and the equilibriumconcentration of the gas in solution. Simply stated, if we increase thesurface to volume ration of contact, we increase the rate of exchange.If we consume the gas (VOC) entering the bubble (or micropore spacebounded by a liquid film), the difference is maintained at a higherentry rate than if the VOC is allowed to reach saturation equilibrium.In our case, of the HVOC, PCE, the consumptive gas/gas reaction of PCEto by products of HCl, CO₂, and H₂O accomplishes this.

The normal equation for the two-film theory of gas transfer is stated:(Metcalf and Eddy, 1991)

Vm=Kg A (C_(S)—C)

where:

Vm=rate of mass transfer

Kg=coefficient of diffusion for gas

A=area through which gas is diffusing

C_(S) =saturation concentration of gas in solution

C=concentration of gas in solution the restatement of the equation toconsider the inward transfer of phase change from dissolved HVOC togaseous HVOC in the inside of the bubble would be:

C_(S)=saturation concentration of gas phase in bubble

C=initial concentration of gas phase in bubble volume

Table 3 gives the Henry's Constants (Hc) for a selected number oforganic compounds and the second rate constants (Rc) for the ozoneradical rate of reaction. The third column presents the product of both(RRC). As a ranking of effectiveness. In actual practice the diffusionis rate-limiting, resulting in the most effective removal with PCE(tetrachloroethylene). TABLE 3 REMOVAL RATE COEFFICIENTS FOR THEMICROBUBBLE/OZONE PROCESS - C-SPARGE Ozone K₂ Second order K₁ RateOrganic Rate Constant^(b) Henry's Removal Compound (M⁻¹ SEC⁻¹)Constant^(b) Coefficient Benzene 2 5.59 × 10⁻³ .0110 Toluene 14 6.37 ×10⁻³ .0890 Chlorobenzene 0.75 3.72 × 10⁻³ .0028 Trichloroethylene 179.10 × 10⁻³ .1540 Tetrachloroethylene 0.1 2.59 × 10⁻² .026 Ethanol .024.48 × 10⁻⁵ .0000008R_(c) · H_(c) = RRCa. From Hoigne and Bader, 1983^(b)From EPA 540/1-86/060, Superfund Public Health Evaluation ManualElimination of the Need for Vapor Extraction

The need for vapor control exists when vapors of VOC's partitioned fromdissolved form into the microbubbles, reach the unsaturated zone,releasing vapors. Without reaction with a decomposing gas, such asozone, a large mass can be transmitted in a short time, creatingpotential health problems near residential basement areas.

The combined extraction/decomposition process has the capacity toeliminate the need for vapor capture. If the decomposition rate withozone exceeds the vertical time-of-travel, vapors will not be producedor their concentration will be so low as to not require capture. Bycontrolling the size of microbubbles and matching them to suitable slowrise times, the need for vapor control is eliminated.

The rise time of bubbles of different sizes was computed for water,giving the upwards gravitational velocity. The upwards velocity providesthe positive pressure to push the bubbles through the porous media,following Darcy's equation. By timing the rise rate in the field; therise time, proportional to upwards pressure, can be calculated. Thebubble size is very important. Once a bubble exceeds the pore cavitysize, it is significantly retarded or trapped. Pulsing of the waterphase provides a necessary boost to assure steady upwards migration andreducing coalesion. UPWARD TIME (MINUTES) FOR BUBBLE VELOCITY UPWARDSMIGRATION DIAMETER IN WATER (3 METERS) (Coarse Sand and Gravel) 10 mm.25 m/s 19 min  2 mm .16 m/s 30 min  .2 mm .018 m/s  240 min Elimination Rate of PCE Relative to Ozone Content

The reaction of ozone with tetrachloroethane (PCE) will producedegradation products of hydrochloric acid, carbon dioxide, and water. Byadjusting the ozone concentration to match the dissolved PCE level, thePCE can be removed rapidly without excess ozone release to the air orrelease of PCE vapor into the unsaturated zone.

Accordingly, the object and purpose of the present invention is toprovide microporous diffusers for removal of contaminants from soil andassociated subsurface ground water aquifer, without requiring applying avacuum for extraction biodegration by-products.

Another object is to provide multi-gas systems to be used in combinationwith the microporous diffusers to promote an efficient removal of poorlybiodegradable organics, particularly dissolved chlorinated solvents,without vacuum extraction.

A further object is to provide that remediation occurs by destroyingorganic and hydrocarbon material in place without release ofcontaminating vapors to the atmosphere.

The invention will be described for the purposes of illustration only inconnection with certain embodiments; however, it is recognized thatthose persons skilled in the art may make various changes,modifications, improvements and additions on the illustrated embodimentsall without departing from the spirit and scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a cross sectional schematic illustration of a soil formationshowing the apparatus of the present invention.

FIG. 2. is shows an enlarged piping schematic of the present inventionof FIG. 1 showing the unique fine bubble production chamber;

FIG. 3. is an electrical schematic for a 3 well system (Model 3503 or3603) of the present invention of FIG. 1;

FIG. 4. shows an internal layout of the Control Module box for a threewell system (M-3503 or M-3603) of the present invention ∘ FIG. 1;

FIG. 5A. shows the geometry of the bottom panel on the Control Moduleidentifying the external connections and ports for three well units(M-3503 & 3603)of the invention of FIG. 1

FIG. 5B. is the left side view of FIG. 5A;

FIG. 6. is a schematic illustration of a soil formation showing theapparatus of the present invention;

FIG. 7. is a perspective view of a Bubbler Sparge Unit for GroundwaterTreatment shown partly in section of the prior embodiment.

FIG. 8. is a front view of FIG. 7; the rear being a mirror imagethereof; is the left side; and the right side;

FIG. 9. is a top elevational view of FIG. 7;

FIG. 10. is a bottom elevational view of FIG. 7;

FIG. 11. is a front elevational view of FIG. 7; the broken line showingthe sparge bubbler unit in-situ for groundwater treatment.

FIG. 12. is an alternate embodiment of a microporous spargepointassembly of the invention of FIG. 1.

FIG. 13. is a outline of Table 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to sparging apparatus for injection ofoxidizing gas in the form of small bubbles into aquifer regions toencourage in situ remediation of subsurface leachate plumes. Inparticular the present invention employs microporous diffusers injectingmulti-gas bubbles into aquifer regions to encourage biodegradation ofleachate plumes which contain biodegradable organics, or Criegeedecomposition of leachate plumes containing dissolved chlorinatedhydrocarbons.

Referring to the FIGS. 1 through 6 there is shown a Sparge System 10consisting of multiple microporous diffusers in combination with anencapsulated multi-gas system, the system 10 consists of a master unit12 and one or more in-well sparging units 14. Each master unit 12 canoperate up to a total of three wells simultaneously, and treating anarea up to 50 feet wide and 100 feet long. Actual performance dependsupon site conditions. Vapor capture is not normally necessary. In thepreferred embodiment, as shown in FIG. 1, and FIG. 2 master unit 12consists of the following: a gas generator 16, a gas feed line 15, acompressor 18, a power source 19, a pump control unit 20, a timer 2. Themaster unit 12 must be firmly mounted on 4×4 posts 40 or building wall42 near in-well sparging units 14. A heavy-duty power cable 44, not over50 feet in length, may be used to run from the power source to themaster unit 12.

Referring to FIGS. 1 and 2, the in-well sparging unit 14 consists of acasing 56, an inlet screen 50 an expandable pacer 52, an upper sitegrout 54, an outlet screen 58, and lower grout 62. Each inwell unit 14includes a fixed packer 24, at least two diffusers 26 hereinafter“Spargepoint(r)™ diffusers” 26, a water pump 28, ozone line 30, checkvalve 32, and fittings 34. As is shown in FIGS. 1 and 2 the diffuser 26employs a microporous diffuser in place of standard slotted well screento improve dispersion of bubbles 60 through soil shown at 84 and improverate of gaseous exchange. A normal 10-slot PVC well screen containsroughly twelve percent (12%) open area. Under pressure most air exitsthe top slits and radiates outward in a starlike fracture pattern,evidencing fracturing of the formation.

Referring to FIG. 2 there is shown a fine bubble production chamber 46positioned in the well casing 56 between the upper well screen 50positioned immediately below fixed packer 24 consisting of a removableclosure plug and the lower plug 48 consisting of the fine bubbleproduction chamber 46 containing bubbles 60 including upper Spargepoint™26 positioned above lower well screen 58 including pump 28 and checkvalve 32. Referring to FIG. 4 there is shown the internal layout of thecontrol module box 12 including an AC/DC power converter 71, and ozonegenerator 72, well gas relays 73 (three wells shown) a compressor 74, amaster relay 75, a main fuse 76. There is also shown a programmabletimer controller 77, a power strip 78, a gas regulator and pressuregauge 79, together with a solenoid manifold 80, a ground fallinterrupter 81 and a cooling fan 82.

Spargepoint diffusers include several unique configurations as follows;

-   -   a. Direct substitute for well screen, 30% porosity 5-50 micron        channel size resistance to flow only 1 to 3 PSI, can take high        volume flow, needs selective annular pack (sized to formation).        High density polyethylene or polypropylene is light weight,        rugged, inexpensive.    -   b. Diffuser on end of narrow diameter pipe riser KVA 14-291.        This reduces the residence time in the riser volume.    -   c. Shielded microporous diffuser which is injected with a        hand-held or hydraulic vibratory hammer. The microporous        material is molded around an internal metal (copper) perforated        tubing and attached to an anchor which pulls the spargepoint out        when the protective insertion shaft is retracted. Unit is        connected to surface with 3/16 or ¼ inch polypropylene tubing        with a compression fitting.    -   d. Thin spargepoint with molded tubing can be inserted down        narrow shaft for use with push or vibratory tools with        detachable points. The shaft is pushed to the depth desired,        then the spargepoint inserted, the shaft is pulled upwards,        pulling off the detachable drive point and exposing the        spargepoint.    -   e. Microporous diffuser/pump combination placed within a well        screen in such a manner that bubble production and pumping is        sequenced with a delay to allow separation of large bubbles from        the desired fine “champagne” bubbles. The pressure from the pump        is allowed to offset the formation back pressure to allow        injection of the remaining fine bubbles into the formation.        IMPROVEMENTS

In the present invention the improvement comprises several now equipmentdesigns associated with the spargepoint diffusers. Most important is thesubmittal for HDPE porous material with well fittings and pass-throughdesign which allows individual pressure and flow control as is shown inFIG. 7.

Secondarily, the push-probe points have been developed for use withpneumatic tools, instead of drilling auger insertion on controls, theright-angle mirror wellhead assembly needs better protection.

Improvements on C-sparger/microporous spargepoint diffuser. One of themajor pass-through spargepoints problems in horizontal sparging is evendistribution of air bubbles. If inflow is attached to the end of ascreen, the pressure drops continuously as air is released from thescreen. The resulting distribution of flow causes most bubbles to beproduced where the connection occurs with flow alternating outwards. Theend of the screen products little or no bubbles.

To allow even distribution of bubbles, either individual spargepointsare bundled (spagetti tube approach) or the spargepoint are constructedin a unique way which allows interval tubing connections with flow andpressure control for each spargepoint region with the proposedarrangement, connecting tubing, to spargepoints passes through thespargepoint internally without interfering with function of producingsmall bubbles on a smooth external surface (2) the tubing penetrationreducing the internal gas volume of the spargepoint, thereby reducingresidence time for oxidative gases (important since ozone has only acertain lifetime before decomposition), and allows 3 to 4 spargepointsto be operated simultaneously with equal flow and pressure. Eachspargepoint can also be programmed to pulse on a timed sequencer, savingelectrical costs and allowing certain unique vertical and horizontalbubble patterns. Spargepoint diffusers can be fitted with F480 Threadwith internal bypass and compression fittings:

Advantages

-   -   (2) fits standars well screen;    -   (3) Allows individual flow/pressure control;    -   (4) Reduces residence time;    -   (5) Allows casing/sparge instead of continuous bubbler.        Use of Injectable Points configured as Moulded: 18 Inch 0.40        inch HDPE moulded into ¼ inch pp tubing or HDPE tubing allows        smooth tube to be inserted into push probe with detachable        point. Use of “Bullet” prepacked Spargepoint diffusers: with KVA        “hefty system” prepacked sand cylinder and bentonite cylinder        placed over tubing and porous point. Also use of a porous point        reinforced with inner metal tube (perforated) to allow strength        throughout tubing resists disintegration of plastic during        insertion.

Use of Pressure/flow headers: Rodometer/mirror: Mirror assembly forflush-mounted rotometer (flowmeter), allows reading from vertical downand controls flow off lateral lines to adjust to back pressure fromvarying types of formations (silt, sand, gravel) below.

It is well recognized that the effectiveness of treatment is dependentupon uniformity of dispersion of the gas as it travels through theformation. A porous structure with appropriate packing matches thecondition of the pores of the soil with thirty percent (30%) poredistribution. The dispersion of bubbles as a fluid can be checked withDarcy's equation.

The use of microporous materials in the “Spargepoint™” 26 to injectgases into groundwater saturated formations has special advantages forthe following reasons:

1. Matching permeability and channel size;

2. Matching porosity;

3. Enhancing fluidity, which can be determined in-situ.

The most effective range of pore space for the diffuser materialselected depends upon the nature of the unconsolidated formation to beinjected into, but the following serves as a general guide:

1. Porosity of porous material: thirty percent (30%);

2. Pore space: 5-200 microns;

-   -   a. 5-20 very fine silty sand;    -   b. 20-50 medium sand;    -   c. 50-200 coarse sand and gravel.

The surrounding sand pack placed between the spargepoint 26 and naturalmaterial to fill the zone of drilling excavation should also becompatible in channel size to reduce coalescing of the produced bubbles.

The permeability range for fluid injection function without fracturingwould follow:

1. 10⁻² to 10⁻⁶ cm/sec, corresponding to 2 to 2000 Darcy's; or

2. 20⁻² to 10⁻⁶ cm/sec; or

3. 100 to 0.01 ft/day hydraulic conductivity.

Permeability is the measure of the ease of movement of a gas through thesoil. The ability of a porous soil to pass any fluid, including gas,depends upon its internal resistance to flow, dictated largely by theforces of attraction, adhesion, cohesion, and viscosity. Because theratio of surface area to porosity increases as particle size decreases,permeability is often related to particle size see Table ???2.

1-8. (canceled)
 9. A method of removal of volatile organic compounds ina soil formation comprises: injecting air including gaseous ozone intowater in the soil formation with gaseous ozone at concentrations toeffect removal of volatile organic compounds by the gaseous ozonereacting with the volatile organic compounds and with the air and theozone injected into the water as fine bubbles with an initial bubblesize in a range of about 5 to 200 μm.
 10. The method of claim 9 whereinthe fine bubbles are sized in accordance with a porosity characteristicof the soil formation.
 11. The method of claim 9 wherein injectingfurther comprises: providing a plurality of injection wells andintroducing the air and ozone as fine bubbles between about 5 to 200 μmthrough the injection wells.
 12. The method of claim 11, furthercomprising intermittently agitating water in the well.
 13. The method ofclaim 9, further comprising periodically pulsing the injected airincluding ozone.
 14. The method of claim 9 wherein injecting furthercomprises: mixing the ambient air with the ozone.
 15. The method ofclaim 9 wherein injecting further comprises: mixing the air with theozone; and delivering the air and ozone through a plurality ofmicroporous diffusers to produce the fine bubbles of air and ozone. 16.The method of claim 9 wherein volatile organic compounds in the soilformation are decomposed by ozone interaction with double bonded carbonatoms of the volatile organic compounds.
 17. The method of claim 9wherein the fine bubbles have an initial bubble size at least between 50to 200 μm.
 18. The method of claim 9 wherein the fine bubbles have aninitial bubble size at least between 20 to 50 μm.
 19. The method ofclaim 9 wherein the fine bubbles have an initial bubble size at leastbetween 5 to 20 μm.
 20. The method of claim 9 further comprising:providing a plurality of injection wells and injecting the ambient airand ozone as fine bubbles through the injection wells by using acorresponding micro-porous diffuser for each one of the plurality ofinjection wells; and surrounding the micro-porous diffusers with a sandpack disposed between the micro-porous diffusers and the surroundingsoil formation.
 21. The method of claim 9 wherein removal of volatileorganic compounds can occur without vapor extraction.
 22. The method ofclaim 9 further comprising agitating with pumped water to disperse saidbubbles through the soil formation.
 23. The method of claim 9 whereinthe soil formation contains chlorinated hydrocarbons.
 24. The method ofclaim 9 wherein the soil formation contains organic and hydrocarbonmaterial.
 25. The method of claim 9 wherein the volatile organiccompounds include chlorinated solvents including dichloroethene,trichloroethene, and/or tetrachloroethene.
 26. The method of claim 9wherein microporous diffusers are used to generate said fine bubbles andthe microporous materials of the microporous diffusers have a pore sizeselected to match a porosity characteristic of the surrounding soilformation.
 27. The method of claim 26 wherein the microporous materialsof the microporous diffusers have a pore size selected to match aporosity characteristic and a permeability characteristic of thesurrounding soil formation.
 28. The method of claim 9 whereinmicroporous diffusers are used to generate said fine bubbles and themicroporous materials of the microporous diffusers have a pore sizeselected to match a permeability characteristic of the surrounding soilformation.
 29. The method of claim 9 further comprises: generating anoxidizing agent comprising ozone at concentrations to effect removal ofcontaminants; mixing air with ozone to produce the air including ozone.30. Apparatus for injection of a gas into aquifer regions for removal ofvolatile organic compounds by reaction with ozone, comprising: a gasgenerator for generating an oxidizing agent comprising ozone forinjection of air including ozone into the aquifer; a microporousdiffuser coupled to the gas generator, the microporous diffuserincluding a body having a porous portion with a pore size in the rangeof about 5-200 μm; and a compressor coupled to the gas generator toprovide the gas to the microporous diffuser at an elevated pressure todeliver microbubbles having an initial diameter in a range of about 5microns to 200 microns into the aquifer regions.
 31. The apparatus ofclaim 30 further comprising: a casing; a packer disposed through thecasing an outlet screen coupled to the casing.
 32. The apparatus ofclaim 31 wherein the outlet screen is coupled to the casing at a lowerportion thereof and with the apparatus further comprising: an inletscreen coupled to the casing at an upper portion of the casing.
 33. Theapparatus of claim 31 wherein the packer is disposed through the casingbetween the inlet and outlet screens coupled to the casing.
 34. Theapparatus of claim 31 wherein the microporous diffuser is disposedoutside of the casing.
 35. The apparatus of claim 31 wherein themicroporous diffuser is disposed within the casing.
 36. The apparatus ofclaim 31 wherein the microporous diffuser is a first microporousdiffuser disposed within the casing and wherein the apparatus furthercomprises: a second microporous diffuser disposed below the casing. 37.The apparatus of claim 31 wherein the casing and apparatus are disposedwithin a well, the well provided on a site having an aquifer, andwherein said apparatus further comprises: an outlet screen portion ofthe casing disposed in the aquifer; and an inlet screen portion of thecasing disposed above said outlet screen.
 38. The apparatus of claim 37,further comprising agitation means for intermittently agitating water inthe well.
 39. A method of removal of volatile organic compoundscomprises: injecting air including gaseous ozone, as bubbles with aninitial bubble diameter less than 200 microns with the gaseous ozone atconcentrations to effect removal of volatile organic compounds in asubsurface aquifer with the bubbles forming at least in part bydelivering the air and gaseous ozone through a surrounding sand packdisposed about a region where the air and ozone are injected into asite.
 40. The method of claim 39 further comprising: determining aporosity characteristic of a site containing the volatile organiccompounds; and wherein the bubbles having an initial bubble diameter inaccordance with the determined porosity characteristic of the site andwith the ozone reacting with the volatile organic compounds.
 41. Themethod of claim 39 wherein the fine bubbles have an initial bubblediameter between 5 to 200 μm.
 42. The method of claim 39 wherein thefine bubbles have an initial bubble diameter between 20 to 50 μm. 43.The method of claim 39 wherein the fine bubbles have an initial bubblediameter between 5 to 20 μm.
 44. The method of claim 39 whereininjecting further comprises: providing a plurality of injection wellsand introducing the air and ozone as in the bubbles through theinjection wells.
 45. The method of claim 39 wherein injecting furthercomprises: mixing the air with the ozone; and delivering the air andozone through a microporous diffuser to produce along with the sand packthe bubbles of air and ozone.
 46. The method of claim 39 whereinvolatile organic compounds in the soil formation are decomposed by ozoneinteraction with double bonded carbon atoms of the volatile organiccompounds.
 47. The method of claim 39 further comprising: providing aplurality of injection wells and injecting the ambient air and ozone asfine bubbles through the injection wells by using a correspondingmicroporous diffuser for each one of the plurality of injection wellsand a plurality of sand packs including the surrounding sand pack, withone of the plurality of sand packs being disposed between each one ofthe micro-porous diffusers and the surrounding soil formation.
 48. Themethod of claim 39 wherein the soil formation contains chlorinatedhydrocarbons.
 49. The method of claim 39 wherein the soil formationcontains organic and hydrocarbon material.
 50. The method of claim 39wherein the volatile organic compounds include chlorinated solventsincluding dichloroethene, trichloroethene, and/or tetrachloroethene. 51.The method of claim 39 wherein a microporous diffuser is used togenerate the fine bubbles and microporous material of the microporousdiffuser has a pore size selected in accordance with the determinedporosity characteristic of the surrounding soil formation.
 52. Themethod of claim 51 wherein the microporous material of the microporousdiffuser has a pore size selected to match the determined porositycharacteristic and a permeability characteristic of the surrounding soilformation.
 53. The method of claim 39 further comprises: generating anoxidizing agent comprising the ozone at concentrations to effect removalof contaminants; mixing the air with the ozone to produce the airincluding ozone.
 54. A method comprises: injecting gaseous ozone into awet soil formation at concentrations to effect removal of volatileorganic compounds in the soil formation by delivery of the gaseous ozonein bubbles and with the gaseous ozone reacting with the volatile organiccompounds.
 55. The method of claim 54 further comprising injecting thegaseous ozone with air; and wherein injecting gaseous ozone with airoccurs in ground water of a subsurface aquifer.
 56. The method of claim54 wherein the bubbles are fine bubbles with an initial bubble size in arange of about 5 to 200 μm.
 57. The method of claim 56 wherein the finebubbles are sized in accordance with a porosity characteristic of thesoil formation.
 58. The method of claim 54 further comprises: injectingthe gaseous ozone through microporous materials to provide the bubbles.59. The method of claim 54 further comprises: injecting the ozonethrough a slotted well screen to provide the bubbles.
 60. The method ofclaim 54 further comprises: injecting the ozone through a slotted wellscreen surrounded with microporous materials to provide the bubbles asmicrobubbles.